One good book, written by, June Culp Zeitner, is Gem and Lapidary
Materials for cutters, collectors and jewelers. Published by
Geoscience Press.

It gives the names of many materials and a fair, to good amount of
on each material.

However !! and this is a BIG however, the book completely LACKS any
visual pictorials of materials.

This is the only drawback to the book, and it is a BIG one in my
opinion !

Yet, the text is informative and few books, if any, offer the amount
of text reading this book has.

The publisher and Zeitner should come out with a companion book,
which thoroughly gives a well documented pictorial of all or most of
the book materials in their rough states to their poor, fair, good
and superior qualities, so that the reader can ascertain not only
what a material is, but what a material might be worth, according to
its poor or superior grade,

If anyone knows a good book, which has excellent photographic quality
in showing all the different grades of materials, from rough, to
slabs, to graded and polished cabs, etc, etc, we all would love to
know !! ??